The Carcinogen Bioassay Data System is used to collect, monitor, store, analyze and report experimental data and results from bioassay operations. It is now in full operation with new bioassay experiments being entered as they are initiated. In the past year, over 250,000 data collection forms were processed and entered into the CBDS data base. During this period, special attention has been given to generating reports and analyzing data. For each compound in the system, there is data on experimental design, an individual animal tumor pathology table and tumor incidence summary table, individual animal non-tumor pathology and tissue count table, survival curve analysis, animal weight curves, and statistical analysis of all lesions occuring at an incidence above 5%. Reports are in the process of being generated for over 200 compounds. Statistical analysis of survival and specific tumor types was established using unadjusted and time-adjusted techniques. The unadjusted methods include the Armitage and Cox test for linear trend and Fisher-Irwin Exact test while the time-adjusted methods involve the Cox-Tarone test for trend. In addition, chemical and bioassay contract information sub-systems are maintained.